Quantitative assessment of cytokines (GRO alpha and IL-10) in human seminal plasma during genitourinary inflammation

Immune regulatory cytokines in seminal plasma of healthy men: A scoping review and analysis of variance

OBJECTIVE

Seminal plasma cytokines are associated with fertility and reproductive health, but progressing their clinical utility is hampered by absence of reference data on concentration ranges of relevant cytokines in healthy men. We employed a systematic approach to assemble current evidence on the concentrations of immune regulatory cytokines present in seminal plasma (SP) of normozoospermic and/or fertile men and evaluated the impact of different platform methodologies for cytokine quantification.

EVIDENCE REVIEW

A systematic literature search was performed utilising PubMed, Web of Science and Scopus. Databases were searched from inception until 30th June 2022 inclusive, using combinations of keywords pertaining to seminal fluid and cytokines, and was restricted to human participants. Original data with values reported as concentration of specific cytokines in SP of men clearly defined as fertile or normozoospermic were extracted from studies written in English.

RESULTS

A total of 3769 publications were initially identified, of which 118 fulfilled the eligibility criteria for inclusion. A total of 51 individual cytokines are detectable in SP of healthy men. The number of studies reporting on each cytokine range from 1 to >20. The reported concentrations for many cytokines linked with fertility status, including IL6, CXCL8/IL8, and TNFA, are highly variable between published studies. This is associated with the different immunoassay methodologies utilised and may be exacerbated by a lack of validation of assays to ensure suitability for SP assessment. Due to the large variation between studies, accurate reference ranges for healthy men cannot be determined from the published data.

CONCLUSIONS

The concentrations of cytokines and chemokines detected in SP is inconsistent and highly variable between studies and cohorts, limiting current capacity to define reference ranges for cytokine concentrations in fertile men. The lack of standardisation in methods used to process and store SP, and variation in platforms used to evaluate cytokine abundance, are factors contributing to the observed heterogeneity. To progress the clinical utility of SP cytokine analysis will require standardisation and validation of methodologies so that reference ranges for healthy fertile men can be defined.

Analysis of the human seminal plasma glycome reveals the presence of immunomodulatory carbohydrate functional groups

A recent analysis of the human sperm N-glycome confirmed the expression of biantennary bisecting type N-glycans and terminal Lewis(x)/Lewis(y) sequences previously implicated in the suppression of the innate and adaptive immune responses, respectively. In this study, glycomic analysis of seminal plasma glycoproteins derived from four fertile men was carried out to determine if the same sequences were expressed on the N- and O-glycome of human seminal plasma glycoproteins. Three major families of N-glycans were detected: (i) high mannose glycans (Man(5-7)GlcNAc(2)); (ii) bi-, tri-, and tetraantennary core-fucosylated complex type N-glycans with antennae terminated with Lewis(x) and/or Lewis(y) sequences; and (iii) bi-, tri-, and tetraantennary core-fucosylated complex type N-glycans with antennae capped with sialic acid. Analysis of the O-glycans revealed Core 1 and Core 2 type structures that are also fucosylated or sialylated or a combination of both. The same high mannose and polyfucosylated N-glycans associated with sperm are also present in seminal plasma. Bisecting type N-glycan expression is greatly decreased compared to sperm, while sialylated glycans are abundant in some individuals and minor in others. In summary, the glycosylation profile of seminal plasma glycoproteins is consistent with the modulation of the adaptive but not the innate arm of the human immune response.

Immunology of the Testis and Male Reproductive Tract

A large body of evidence points to the existence of a close, dynamic relationship between the immune system and the male reproductive tract, which has important implications for our understanding of both systems. The testis and the male reproductive tract provide an environment that protects the otherwise highly immunogenic spermatogenic cells and sperm from immunological attack. At the same time, secretions of the testis, including androgens, influence the development and mature functions of the immune system. Activation of the immune system has negative effects on both androgen and sperm production, so that systemic or local infection and inflammation compromise male fertility. The mechanisms underlying these interactions have begun to receive the attention from reproductive biologists and immunologists that they deserve, but many crucial details remain to be uncovered. A complete picture of male reproductive tract function and its response to toxic agents is contingent upon continued exploration of these interactions and the mechanisms involved.

Effect of interleukin-1 receptor antagonist gene deletion on male mouse fertility

Members of the IL-1 family are pleiotropic cytokines that are involved in inflammation, immunoregulation, and other homeostatic functions in the body. IL-1alpha, IL-1beta, and the IL-1 antagonistic molecule [IL-1 receptor antagonist (IL-1 Ra)] are present in the testis under normal homeostasis, and they further increase upon infection/inflammation. In the present study, we examined the effect of IL-1 Ra gene deletion on male mouse fertility. Male mice [wild type (WT) and IL-1 Ra knockout (KO)] were mated with WT females, and the birth and number of offspring were recorded 21-45 d after mating. Furthermore, the concentration, motility, and morphology of sperm isolated from the cauda of the epididymis were evaluated. The ability of the calcium ionophore (A23187) to induce acrosome reaction (AR) in the sperm of WT and IL-1 Ra KO mice was compared with their ability to fertilize in vitro oocytes from WT females. The direct effect of IL-1alpha and IL-1beta on AR and abnormal morphology in sperm from WT were evaluated. The levels of IL-1alpha and IL-1beta in the testes of WT and IL-1 Ra KO mice were examined by specific ELISA and real-time PCR. Our results show a significant reduction in the capacity of IL-1 Ra KO male mice to fertilize WT females (P < 0.05). Furthermore, the number of offspring in mice fertilized with IL-1 Ra KO male mice was significantly lower than with WT males (P < 0.05). Sperm concentration and the percentage of motile sperm from IL-1 Ra KO and WT were similar; however, the percentage of sperm with abnormal morphology (mainly in the head) and acrosome-reacted sperm cells were significantly higher in the IL-1 Ra KO, compared with that of WT males (P < 0.05). In vitro, the ability of sperm from IL-1 Ra KO male mice to fertilize oocytes from WT females was significantly lower than sperm from WT mice (P < 0.05). In addition, the percentage of reacted sperm from IL-1 Ra KO, spontaneously without ionophore induction, was significantly higher than from WT (P < 0.05). Sperm from WT underwent induction of AR only by ionophore; however, sperm from IL-1 Ra KO were unable to undergo the AR by ionophore, indicating that they are induced and, thus, are inactive in fertilization. Testicular IL-1alpha and IL-1beta levels were significantly higher in IL-1 Ra KO, compared with WT male mice (P < 0.05). The addition of recombinant IL-1alpha or IL-1beta to sperm from a WT mouse induced their AR, and significantly increased abnormal sperm morphology, as compared with controls (P < 0.05). This effect was neutralized by the addition of IL-1 Ra. Our results indicate the involvement of IL-1 in sperm physiology, affecting its morphology and fertilization ability. Higher than homeostatic levels of IL-1 in the testis, as observed in IL-1 Ra KO mice, impaired the ability of sperm to fertilize oocytes. Together, these results may explain some of the male infertility cases with an infection/inflammation background and may hint at the ability to use IL-1 Ra in future therapeutic strategies in these cases.

Role of reactive oxygen species and antioxidants on pathophysiology of male reproduction

The excessive generation of reactive oxygen species (ROS) by abnormal spermatozoa and contaminating leukocytes has been defined as one of the few etiologies for male infertility. Administration of antioxidants in patients with 'male factor' infertility has begun to attract considerable interest. The main difficulty of such an approach is our incomplete understanding of the role of free radicals in normal and abnormal sperm function leading to male infertility. Mammalian spermatozoa membranes are very sensitive to free radical induced damage mediated by lipid peroxidation, as they are rich in polyunsaturated fatty acids. Limited endogenous mechanisms exist to reverse these damages. ROS attacks the fluidity of the sperm plasma membrane and the integrity of DNA in the sperm nucleus. ROS induced DNA damage accelerate the germ cell apoptosis. Unfortunately spermatozoa are unable to repair the damage induced by excessive ROS as they lack the cytoplasmic enzymes required to accomplish the repair. Assessment of such oxidative stress status (OSS) may help in the medical treatment. Treatment strategies must be directed toward lowering of ROS levels to keep only a small amount necessary to maintain normal cell function.

Adjudin-mediated junction restructuring in the seminiferous epithelium leads to displacement of soluble guanylate cyclase from adherens junctions

A plethora of evidence supports the role of cyclic nucleotides in junction restructuring. For instance, studies have shown cGMP to be a key regulator of junction assembly and disassembly in different in vitro and in vivo systems. In this study, we examine the role of soluble guanylate cyclase (sGC) in junction restructuring in the seminiferous epithelium of the rat testis. First, the interaction of soluble guanylate cyclase beta1 (sGCbeta1; sGC is a heterodimer comprised of an alpha and a beta subunit) with proteins that constitute adherens and tight junctions in the testis was demonstrated. By immunoprecipitation, sGCbeta1 was found to associate with occludin, JAM-A, and ZO-1, as well as with cadherin, catenin, nectin, afadin, ponsin, and espin, suggestive of its role in cell junction dynamics. These results were corroborated in part by immunohistochemistry experiments, which revealed that the localization of sGCbeta1 was largely restricted to the site of the apical and basal ectoplasmic specialization. Next, the role of sGC in junction dynamics was addressed by using an in vivo model of junction restructuring. Administration of Adjudin--a chemical entity known to specifically perturb adhesion between Sertoli and germ cells (i.e., round and elongate(ing) spermatids and most spermatocytes)--resulted in a approximately 1.5-fold increase in sGCbeta1, coinciding with the loss of germ cells from the epithelium. More importantly, the ability of sGCbeta1 to associate with cadherin increased approximately three-fold during Adjudin-mediated restructuring of Sertoli-germ cell junctions, whereas its interaction with tight junction proteins (i.e., occludin and ZO-1) decreased. Taken collectively, these results suggest that sGC participates in the remodeling of cell junctions during spermatogenesis.

The relationship between immunosuppressive activity and immunoregulatory cytokines in seminal plasma: influence of sperm autoimmunity and seminal leukocytes

While the contributions of prostasomes, polyamines and prostaglandins to the immunosuppressive activity (ISA) of human seminal plasma have been well-characterised, the contribution of immunoregulatory cytokines found in seminal plasma has received relatively little attention. Semen samples were collected from adult men displaying normospermic parameters, sperm antibodies or substantially elevated seminal leukocytes. Samples were processed through ultracentrifugation and dialysis (<3500Da) to remove prostasomes, polyamines and prostaglandins, and then assayed for ISA by an in vitro T lymphocyte inhibition assay, as well as by specific immunoassays for transforming growth factor beta(1) (TGFbeta(1)), interleukin-10 (IL-10), activin A and the activin-binding protein, follistatin. Seminal plasma from all groups retained substantial ISA following processing. Compared with normospermic men, this 'large' molecular weight ISA fraction was significantly increased in a subset of men with sperm antibodies, but was not altered in the group with elevated leukocytes. There was no relationship between ISA and any cytokine examined, and only TGFbeta(1) was present at levels sufficient to contribute to ISA. Inhibition with a TGFbeta-specific antibody reduced ISA in seminal plasma by approximately 50%. Across all patients, TGFbeta(1) levels were positively correlated with sperm numbers in the ejaculate and with activin A, but not with follistatin or IL-10. Activin A and IL-10 also displayed a positive relationship, and elevated leukocytes was associated with a significant elevation of IL-10 and activin A, but not TGFbeta(1). It is concluded that 'large' molecular weight molecules, the most important of which appears to be TGFbeta(1), make a significant contribution to immunosuppression by human seminal plasma.

Relation between immunosuppressive PGE(2) and IL-10 to pro-inflammatory IL-6 in seminal plasma of infertile and fertile men

In vitro studies have reported that seminal plasma of fertile men has more inhibitory mitogenic effect and higher suppressive activity on antibody-dependent cellular cytotoxicity than seminal plasma from infertile males. Is it possible that variations in the seminal plasma composition could explain these results? The present study was conducted to investigate the relation between immunosuppressive PGE(2) and IL-10 to pro-inflammatory IL-6 in seminal plasma of infertile and fertile men. Utilizing specific ELISA commercial kit, semen samples from 45 infertile undiagnosed and 25 fertile men were examined for the presence of PGE(2), IL-10, and IL-6. The IL-6 concentration in seminal plasma of infertile men was significantly higher than that of fertile men (p<.0 4). However, levels of IL-10 were lower for the semen of infertile men than that of fertile men (p<.04). No differences were observed in PGE(2) concentrations between both groups. Increase in pro-inflammatory cytokines, such as IL-6, and decrease in immunosuppressive ones, such as IL-10, could alter the tolerance to sperm cell in male and female tracts and reduce the favorable conditions to reach the fecundation and implantation. It is necessary to conduct further studies that include other pro- and anti-inflammatory substances to evaluate the importance of the immune balance of semen in human fertility.

Distinct expression pattern of cytokines in semen of men with genital infection and oligo-terato-asthenozoospermia

PROBLEM

The objective of this study was to evaluate the possible relevance of cytokines in seminal plasma (SP) of patients with accessory gland infection and oligoterato-asthenozoospermia.

METHOD OF STUDY

Semen samples were obtained by masturbation from 90 men and were examined for the presence of interleukin (IL)-2, IL-6, IL-8, IL-11 and soluble CD23 (sCD23) by enzyme-linked immunosorbent assay. Five groups were included: (1) fertile men (n = 20), (2) infertile men with varicocele and oligo-teratoasthenozoospermia (V-OTA, n = 20), (3) infertile men with genital infection and OTA (INF-OTA, n = 20), (4) infertile men with idiopathic testicular lesion and OTA (ITL-OTA, n = 20) and (5) infertile men with azoospermia (AZOO, n = 10).

RESULTS

We found that the mean level of IL-2 was higher in SP from infertile men compared with SP from fertile men (P < 0.05). Mean levels of IL-6, IL-8, IL-11 in SP of INF-OTA were higher than that of all other groups (P < 0.05, P < 0.05, P < 0.001, respectively). However, no significant differences could be detected between other groups. A significant increase was noted in sCD23 levels in SP from men with ITL-OTA compared with all other groups (P < 0.01). We have not observed any correlations between IL-2, IL-6, IL-8, IL-11 and sCD23 levels in SP and semen parameters. Spearman's correlation coefficient revealed that there was a significant association between IL-6, IL-8, IL-11 levels in men with INF-OTA.

CONCLUSION

The measurement of each cytokine separately in the SP of men with INF-OTA, in spite of the existing significant differences, does not have a diagnostic value in male infertility. However, a combined determination of IL-6, IL-8, IL-11 in the SP of men with genital infection and oligo-terato-asthenozoospermia may provide clinically useful information for the diagnosis of male accessory gland infection.

Role of genitourinary inflammation in infertility: synergistic effect of lipopolysaccharide and interferon-gamma on human spermatozoa

Pro-inflammatory cytokines are elevated in the semen of patients with genitourinary inflammation (GUI). Whether this increase in cytokines in GUI patients plays any critical role in male factor infertility is not clear. The present study investigated the in vitro effects of two important pro-inflammatory cytokines, lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma), on sperm motility, viability, membrane integrity and motion parameters. Washed spermatozoa from healthy donors were incubated with LPS (0.1 mg/mL) or IFN-gamma (0.1 mg/mL) alone or in combination. Sperm motility, viability, membrane integrity and computer-assisted motion were evaluated at various time intervals (0, 30, 60 and 180 min) after treatment. Sperm membrane integrity was analysed using the hypo-osmotic swelling test (HOST). LPS and IFN-gamma individually did not alter sperm viability or motility, but their combination showed a significant time-dependent decrease (p < 0.05) in sperm motility, viability and membrane integrity. Sperm motion parameters (straight-line velocity, curvilinear velocity, mean linearity, or amplitude of lateral head displacement) were not affected by LPS or IFN-gamma at the concentrations used in this study. These data suggest that the combination of LPS and IFN-gamma is detrimental to human spermatozoa and may contribute to male factor infertility in patients with chronic GUI.

CXC-chemokines stimulate invasion and chemotaxis in prostate carcinoma cells through the CXCR2 receptor

BACKGROUND

Metastasis of prostate carcinoma requires invasion through the basement membrane, a thin extracellular matrix that underlies the epithelial cells, which must be breached by tumor cells invading into surrounding tissue. The CXC-chemokines, which have been shown to promote the migration of neutrophils and carcinoma cells, are candidates to influence prostate carcinoma-cell invasion.

METHODS

CXC-chemokines were examined for the ability to stimulate prostate cell line PC3 invasion in vitro through a reconstituted basement membrane and long-term migration and short-term adhesion to laminin, a major component of the basement membrane.

RESULTS

PC3 cells responded to IL-8 and GROalpha with a 1. 6-2-fold increase in invasion through reconstituted basement membrane. A corresponding 2-3-fold increase in chemotaxis toward IL-8 and GROa was seen on laminin. Anti-CXCR2 antibody inhibited IL-8-stimulated migration. Expression levels of the beta(1) integrins were not changed by IL-8, and alpha(6beta1) integrin was used for both stimulated and baseline migration. In addition to the increases in migration and invasion, 2-6-fold transient increases in adhesion on laminin were seen with both IL-8 and GROalpha.

CONCLUSIONS

These results suggest that the CXC-chemokines stimulate migration and invasion in part by altering the activation state of the beta(1) integrins. The CXC-chemokines act on prostate carcinoma cells through the CXCR2 receptor to promote behavior important for metastasis, and as such may be important in prostate carcinoma progression and metastasis.

Male infertility and erectile dysfunction in spinal cord injury: a review

OBJECTIVE

To review the pathophysiology, evaluation, and management of erectile dysfunction and infertility in spinal cord injury (SCI).

STUDY SELECTIONS

Studies that covered various treatment options and their contraindications, complications, or side effects, including sildenafil (Viagra), intracavernosal injection therapy, topical medications and a urethral delivery system, a vacuum erection device, and penile prostheses. Other studies covered the effects of SCI on reproduction: spermatogenesis and testicular function, and seminal constituents. In addition, assisted reproductive techniques were compared: external vibratory stimulation, electroejaculation, testicular sperm aspiration, and intracytoplasmic sperm injection.

CONCLUSION

Goal-directed therapy is the mainstay of treatment of erectile dysfunction in men with or without SCI. The choice of therapy is often defined more by the needs of the patient's sexual relationship than by his erectile dysfunction. The majority of men with SCI are infertile because of a combination of ejaculatory dysfunction, impaired spermatogenesis, and poor semen quality. Although many technological advances have evolved to overcome ejaculatory dysfunction, the sperm density, motility, and function remain poor. Until these parameters are improved, men with SCI will have to pursue more financially and emotionally taxing procedures. Further studies to elucidate the cellular and molecular mechanisms of diminished sperm quality are needed. Addressing the issues of erectile dysfunction and male infertility may help to preserve the relationship between the patient and his partner.

Expression of IL-12, IL-10, PGE2, sIL-2R and sIL-6R in seminal plasma of fertile and infertile men

The involvement of cytokines and other immunoregulatory factors in male infertility is still unclear. In the present study we compared the levels of IL-12, IL-10, PGE2, sIL-2R and sIL-6R in the seminal plasma (SP) of fertile and infertile men. Four groups were included: fertile donors (FERT), infertile men with azoospermia (AZOO), and infertile men with either oligoterato-asthenoazoospermia (OTA), or OTA with genital infection (OTA-INF). Cytokines and cytokine-soluble receptors in semen were evaluated by specific ELISA commercial kits. The levels of IL-12, sIL-2R and sIL-6R were similar in SP of fertile and infertile men. The mean levels of IL-10 in the SP of FERT, OTA and AZOO were 5.6 +/- 0.9, 4 +/- 2.8 and 8 +/- 3.5 pg ml-1, respectively, and did not differ significantly. The mean level of IL-10 in SP from OTA-INF (0.9 +/- 0.5 pg ml-1) was significantly lower than that for FERT (5.6 +/- 1.9 pg ml-1; P = 0.02) and AZOO (8.2 +/- 3.4 pg ml-1; P = 0.05), but not significantly different from that for OTA (3.7 +/- 2.1 pg ml-1). The mean SP level of PGE2 was significantly lower in SP of OTA-INF than FERT (7.67 +/- 2.26 and 19.67 +/- 3.69 micrograms ml-1, respectively; P < 0.02). In conclusion, the seminal plasma from fertile and infertile men contained similar levels of IL-12, sIL-2R and sIL-6R. However, the levels of IL-10 were significantly lower in SP from OTA-INF compared to FERT and AZOO. Our results indicate that specific cytokines and their soluble receptors are involved in the male reproductive system.

Decreased levels of interleukin-12 are not correlated with leukocyte concentration and superoxide dismutase activity in semen of infertile men

The interleukin (IL)-12 levels and the superoxide dismutase (SOD) activity were determined in the seminal plasma of fertile and infertile men with or without leukocytospermia by ELISA. The IL-12 levels differed significantly among the fertile and infertile groups, with the infertile groups showing lower levels that were not modulated by leukocytospermia. The SOD activity did not differ significantly among the fertile and infertile groups and was not correlated with the IL-12 levels. The positive correlation with sperm concentration suggests that IL-12 may have a direct or indirect role in male fertility/infertility and that its levels are not modulated by the presence of leukocytes in the semen.